Technical Abstract:
Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO2) budget, because wind erosion contributes to the C cycle by selectively removing4 SOC from vast areas and transports C dust quickly offshore; augmenting the net loss of carbon from terrestrial systems. However, the contribution of wind erosion to rates of carbon release and sequestration is poorly understood. Here we show that SOC dust emission is omitted from national carbon accounting, is an under-estimated source of CO2 and a largely unaccounted-for, likely accelerant of SOC decomposition. We developed a first approximation to SOC enrichment for a dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO2-e y-1) and Australian agricultural soils (0.4 Tg CO2-e y-1). These amount to under-estimates for CO2 emissions of ~10% from combined C pools in Australia (yr=2000), ~5% from Australian Rangelands and ~3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission also likely represents a considerable underestimate from those nation’s carbon accounts.